string s = "你不是我要找的人";
for (int i = 0; i < s.Length; i++)
//s[i]是对字符串每个字符的提取
Response.Write(s[i].ToString() + "<br />");
string[] ss = { "aacc", "adad", "ss", "byed" };
foreach (string d in ss)
{
//如果字符串d中包含字符'a',也可以用"aa",表包含字符串"aa"
if (d.Contains('a'))
Response.Write(d + "<br />");
}